Chemistry of Life

When Amanda poured some of the liquid in a test tube, she noticed that the edges of the water curved upward, which is an example of __________.

• cohesion

• acids

• adhesion

• bases

When Pol filled another test tube to the top, the liquid formed a low dome, which is evidence of __________.

• cohesion

• acids

• adhesion

• bases

When Amanda added table salt to the first test tube and shook it, she noted that the liquid had dissolved the __________.

• solute

• solvent

• acid

• base

Pol measured the pH of the sample to be 7, which is a _____________ value.

• neutral

• acidic

• basic

• positive

Which of the following observations BEST demonstrates water’s special property of cohesion?

• water forms droplets of dew on a spider web in the

• a spoon held near a stream of water from a tap deflects the water towards itself

• a drop of water behaves like glue to stick a slip of paper to a window

• water can dissolve other substances, such as sugar and salt

Blood is a mixture of a variety of materials. Some of the materials are dissolved in the fluid portion of blood. Other materials, such as blood cells, do not dissolve but move along with the blood.

For these reasons, blood is an example of which type of mixture?

• a solvent

• a solution

• a suspension

• a buffer

Buffers are________________that can react with strong acids and bases to ____________________

• strong acids or weak bases/ prevent sudden changes in pH

• weak acids or weak bases/ increase the effect of the base

• strong acids or weak bases/ increase the effect of the base

• weak acids or weak bases/prevent sudden changes in pH

How are electric charges distributed within the atom?

• Positive and negative charges are distributed evenly.

• Positive charges are concentrated in the nucleus; negative charges surround the nucleus.

• Negative charges are concentrated in the nucleus; positive charges surround the nucleus.

• Both positive and negative charges are concentrated in the nucleus.

Deuterium is an isotope of hydrogen. It has a mass number of two. Which describes a deuterium atom?

• a nucleus of one proton and one neutron, which is orbited by one electron

• a nucleus of one proton, which is orbited by one neutron and one electron

• nucleus of one neutron, which is orbited by one electron

• a nucleus of two neutrons which is orbited by two electrons

A carbon atom has 6 protons and 6 electrons. Carbon has three naturally occurring isotopes, carbon-12, carbon-13, and carbon-14. Which of these statements is true about carbon and its isotopes?

• All carbon atoms have six neutrons.

• All carbon atoms have six protons and six electrons.

• Atoms of all carbon isotopes have either more than 6 electrons or fewer than 6 electrons

• Atoms of some naturally-occurring carbon isotopes may have twelve neutrons